Sole of a shoe having a preferred flexing zone, and shoe having such an outer sole

ABSTRACT

A sole of a shoe, extending in a longitudinal direction representative of the main axis of the foot, has an anterior part that is able to receive the forefoot, a central part that is able to receive the midfoot, and a posterior part that is able to receive the heel, the sole having, in the anterior part, a preferred flexing zone extending in an oblique direction with respect to the main axis of the foot.

TECHNICAL FIELD OF INVENTION

The field of the invention is that of shoes, in particular used for the practice of a physical activity, and in particular for the practice of sport whether urban or outdoors.

PRIOR ART

Sports activities such as walking, jogging and running are activities practiced on a regular basis, even daily, for some people. This activity causes repeated impacts at the feet, impacts which are transmitted to the joints of the upper stages and which are known to favour in the short, medium or long term the appearance of Musculo-Skeletal Disorders (MSDs).

These MSDs can range from simple pain to disabling injuries such as fatigue fractures, severe wear of cartilage or tendonitis, which forces the person to reduce, and even in certain cases, stop their practice. These disorders can be cared for, but lead to reoccurrences in most cases.

To limit the risk of the appearance or recurrence of MSDs linked to the practice of sports, it is imperative to control the unfolding of the step so as to maintain a kinematics of the foot that optimises the yield and that limits the deleterious effects (pressure peaks, vibrations, instabilities). This control can be done conscientiously, by an informed practicer, and it can also be facilitated by using a suitable shoe.

Shoes form the main equipment of the athlete (walking and running), and are increasingly specific to a practice and to a sport. They must make it possible to respond to certain needs linked to the sports activity, particularly in terms of adherence, the type of impact and movement expected. Thus, for example, manufacturers favour a more cushioning sole for a running shoe on hard ground, or a sole and a wrapping of the foot that are stiffer for a hiking shoe on soft ground.

Although these improvements make it possible to improve the general comfort of the athlete as well as their performance, all these specificities often make for losing sight of the fundamental physiological and biomechanical aspect of the foot.

Indeed, beyond the impact of the heel, it is the entire kinematics (or unfolding) of the step that is capital and which has to comply with certain rules.

DISCLOSURE OF THE INVENTION

In this context, the invention aims to propose a sole of a shoe, extending in a longitudinal direction (L) representative of the main axis of the foot (P), and having an anterior part that is able to receive the forefoot, a central part that is able to receive the midfoot and a posterior part that is able to receive the heel, said sole having in the anterior part a preferred flexing zone extending in an oblique direction with respect to the main axis of the foot (P).

Main axis of the foot (P), or static axis of the foot, means the axis that passes through the middle of the heel and through the middle of the second toe.

Thus, the sole according to the invention makes it possible to respect the flexing movement of the foot only at the five metatarsal phalangeal joints of the foot and to contain any other joint mobilisation of the foot so as to limit the risk of injury by proposing the creation of an artificial flexing zone located at the forefoot.

In addition to the characteristics mentioned in the preceding paragraph, the outsole according to the invention can have one or more additional characteristics among the following, taken individually or according to any technically permissible combination:

-   -   the sole has in the anterior part a plurality of preferred         flexing zones extending in an oblique direction with respect to         the main axis of the foot P);     -   said preferred flexing zone is located in the anterior part         receiving the forefoot and as a projection of the metatarsal         phalangeal heads of the foot;     -   said sole has, in the preferred flexing zone, a hardness at         least 10% lower with respect to the rest of said sole;     -   said preferred flexing zone has a height, extending in a         longitudinal direction (L), comprised between 3 and 40 mm;     -   said preferred flexing zone is oriented according to a flexing         fold axis principal (F), itself oriented according to an angle         of 105°±15° with respect to the main axis of the foot (P);     -   said sole has, in the preferred flexing zone, at least one         groove oriented according to the flexing fold axis principal         (F);     -   said sole is made of a first material and has, in the preferred         flexing zone, an inclusion of a second material of the same         nature and having a density less than the density of the first         material used for the rest of the sole;     -   the second material has a density at least 10% less than the         density of the first material;     -   said sole is made of a first material and has, in the preferred         flexing zone, an inclusion of a second material of a different         nature and having a hardness less than the hardness of the first         material used for the rest of the sole;     -   the second material has a hardness at least 10% less than the         hardness of the first material;     -   said preferred flexing zone is located at a distance comprised         between 60 and 75% of the total length of the sole from its rear         end;     -   said preferred flexing zone extends over a portion or over the         entire width of the sole;     -   said sole has a strip with extra thickness located at an edge of         said preferred flexing zone or at two edges of said preferred         flexing zone;     -   said strip with extra thickness is oriented according to the         flexing fold axis principal (F), itself oriented according to an         angle of 105°±15° with respect to the main axis of the foot (P);     -   said strip with extra thickness forms a means of gripping of the         anterior part of the outsole;     -   said sole is a flexible sole with an elastomer base or a rigid         sole with a thermoplastic material base;     -   said sole comprises an outsole intended to come into contact         with the ground and a midsole, said preferred flexing zone         extending in an oblique direction with respect to the main axis         of the foot (P) being arranged at said outsole.

The invention also has for object a shoe comprising a sole according to the invention.

Advantageously, the shoe is a walking shoe, a running shoe, a sports shoe, a football shoe or a rugby shoe.

The invention and its different applications will be understood better when reading the following description and examining the accompany figures.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention shall appear when reading the following description, in reference to the accompanying figures, which show:

FIG. 1 shows a cross-section view along the median plane of a sports shoe according to the invention;

FIG. 2 shows a bottom view of a first embodiment of a sports shoe comprising a sole according to the invention;

FIG. 3 shows a bottom view of a second embodiment of a sports shoe comprising a sole according to the invention;

FIG. 4 shows a cross-section view along the longitudinal axis of the shoe of a first embodiment of the structure of the outsole according to the invention at the flexing zone;

FIG. 5 shows a cross-section view along the longitudinal axis of the shoe of a second embodiment of the structure of the outsole according to the invention at the flexing zone;

FIG. 6 shows a cross-section view along the longitudinal axis of the shoe of a third embodiment of the structure of the outsole according to the invention at the flexing zone;

FIG. 7 shows a projection on the foot of the flexing zone arranged at the outsole of a sports shoe according to the invention;

FIG. 8 shows a cross-section view along the longitudinal axis of the shoe of a fourth embodiment of the structure of the outsole according to the invention at the flexing zone;

FIG. 9 shows a bottom view of a third embodiment of a sports shoe comprising a second embodiment of an outsole according to the invention.

For increased clarity, identical or similar elements are marked with identical reference signs on all the figures.

DETAILED DESCRIPTION OF AN EMBODIMENT

FIG. 1 shows a cross-section view of an embodiment of a shoe according to the invention. FIG. 2 shows a bottom view of a first example of a sports shoes comprising a sole according to the invention. FIG. 3 shows a bottom view of a second example of a sports shoe comprising a sole according to the invention.

Median plane means the plane that separates the left half from the right half of the body. Sagittal plane means a plane parallel to the median plane.

Transverse plane means a horizontal plane and therefore perpendicular to the median plane and that separates the body into a cranial portion and a caudal portion.

Frontal (or coronal) plane means a plane perpendicular to the median plane and to the transverse plane and that separates the body into an anterior (ventral) part and a posterior (dorsal) part.

FIG. 1 shows an embodiment of a shoe 100 according to the invention. In this embodiment, the shoe 100 is a sports shoe or sportwear shoe.

Conventionally, and as shown in FIG. 1, the sports shoe 100 according to the invention comprises an stem 20 delimiting a housing intended to receive a foot (not shown). The stem 20 is closed in the lower part by a mounting midsole 30 so as to form a complete volume. This mounting midsole 30 can have cushioning and comfort characteristics. It is for example made using several pieces of leather, canvas, fabric for example made of polyester and/or ethylene vinyl acetate (EVA), or indifferently any other synthetic material known to those skilled in the art.

The sports shoe 100 also comprises a sole 10 on which the mounting midsole 30 is sewn or is glued. According to the first embodiment shown in FIGS. 1 to 3, the sports shoe 100 is a walking shoe, a sports shoe, or a running shoe having a relatively flexible sole 10 formed from a base of foam material and/or that can be deformed manually (typically a material that has a hardness less than 50 Shore A).

The sole 10 forms the base of the sports shoe 100 and is intended to be in contact with the ground. The sole 10 conventionally extends from the front to the rear of the shoe 100 along a longitudinal axis (L) that corresponds to the main axis of the foot (P).

The sole 10 comprises three distinct parts that each fulfil a role in the maintaining and the positioning of the foot in the shoe 100:

-   -   a first part 12 located at the front of the shoe allowing for         the support of the forefoot, called in what follows anterior         part 12;     -   a second part 13 located at the rear of the shoe allowing for         the support of the heel, called in what follows posterior part         13, and;     -   a third part 14 located between the two others providing the         support of the midfoot, called in what follows central part 14.

Each one of the parts 12, 13, 14 is defined and dimensioned so as to form a global foot profile proposing a support for the foot that is the most enveloping possible and the closest as possible to the foot profile of the foot, thus preserving the anatomical and biomechanical balance of the athlete.

The sole 10 is comprised by the association of several layers and/or materials that have different properties (for example hardness, cushioning, etc.) that can be located locally at different places.

Thus, the sole 10 is comprised of an outsole 15, called wearing, intended to be in contact with the ground for example in one or more layers of elements from the following list: polyurethane; elastic thermoplastic polyurethane, rubber.

The outsole 15 is advantageously textured and can have means that favour gripping on a particular ground such as for example sculptures, flexible cleats of which the shape and the geometry can vary according to the programme of use of the sports shoe 100. Cleat is defined as an element, generally a more or less flexible protuberance, lining the outsole of sports shoes so as to provide better adherence on the ground according to the nature of the ground.

The sole 10 can also comprise at least one cushioning element 17 to cushion the impacts. The cushioning element 17 is generally located in the posterior part 14 and/or in the anterior part 12. The cushioning element 17 is for example made from a material from the following list: encapsulated air, gel, expanded thermoplastic polyurethane (TPU), expanded ethylene vinyl acetate (EVA), or any other thermoplastic elastomer.

The sole 10 also comprises a midsole 16 on which the mounting midsole 30 is secured. The midsole 16 plays an important role in the general stability of the foot. This midsole 16 is comprised for example of foam or foams made from EVA and/or of foam or foams made from TPU the densities and the hardnesses of which can vary according to the needs. This midsole 16 can also comprise structural reinforcements located facing the internal arch of the foot or located from the heel until the forefoot. It is also inside this midsole 16 that the various cushioning technologies are located.

The sole 10 according to the invention has in its anterior part 12, at least one preferred flexing zone 41 making it possible to favour and to guide the folding of the shoe during the unfolding of the foot in a particular zone, chosen and predefined of the anterior part 12 of the sole 10.

The preferred flexing zone 41 extends in an oblique direction with respect to the main axis of the foot (P).

The flexing zone 41 extends longitudinally in a direction parallel to a straight line F forming an angle a of 105°±15° with respect to the main axis of the foot P, (i.e. according to an angle of 15°±15° with respect to the transverse axis T perpendicular to the main axis P of the foot) as shown in FIG. 7. The obliquity of the flexing zone 41 is carried out in such a way that the medial edge of the preferred flexing zone 41 is further forward than the lateral edge of the preferred flexing zone 41, with respect to the main axis (P) of the foot.

This flexing zone 41, located in the anterior part receiving the forefoot and as a projection of the metatarsal phalangeal heads of the foot, originates at the rear of the necks of the heads of the metatarsals (and advantageously up to a maximum of 2 cm at the rear according to the type of shoe) and terminates at the front of the metatarsal heads (and advantageously up to a maximum of 2 cm at the front according to the type of shoe). The flexing zone 41 is oriented according to an oblique flexing fold axis F with respect to the longitudinal axis L of the shoe 100, and extended along the longitudinal axis L over a height comprised between 3 and 40 mm.

The preferred flexing zone 41 is located at a distance comprised between 60 and 70% of the total length of the sole 10 with respect to the posterior end of the sole 10.

The preferred flexing zone 41 extends over a portion or the entire width of the sole 10.

FIG. 7 shows a projection on the foot of this flexing zone 41 arranged in the sole 10 of the sports shoe 100. As shown in FIG. 7, this flexing zone 41 is advantageously chosen and corresponds to the contact zone of all the metatarsal phalangeal heads of the foot.

The obliquity of the flexing zone 41 with respect to the longitudinal axis L is directly related to the support zone of the anterior arch of the foot, i.e. in an oblique direction that is oriented from the front towards the rear of the foot and from the medial edge towards the lateral edge of the foot.

The sole 10 has in this flexing zone 41 a hardness that is lower than the rest of the sole 10. Advantageously, the hardness in this flexing zone 41 is at least 10% lower than the hardness of the rest of the sole 10.

According to a first embodiment shown in FIGS. 2 to 6, the preferred flexing zone 41 is arranged at the outsole 15.

In this first embodiment, the sole 10 according to the invention has in its structure, and more particularly in the anterior part 12 of the outsole 15, at least one groove 40, and more particularly a plurality of grooves, oriented obliquely with respect to the main axis of the foot (P). The grooves 40 create a primer of the sole 10, in the mechanical sense of the term, making it possible to favour and to guide the folding of the shoe during the unfolding of the foot in a particular preferred zone, chosen and predefined of the anterior part 12. Typically, the grooves 40 are located in the zone, called flexing zone 41, symbolised by a rectangle in a dotted line in FIGS. 2 to 6.

The grooves 40 are grouped together in this preferred flexing zone 41 that extends over a portion or on either side of the sole 10 (i.e. between the interior and the exterior of the sole 10).

The grooves 40 arranged in this flexing zone 41 also follow this general orientation of the flexing zone 41 in such a way that the grooves 40 are substantially oriented according to an angle a of 105°±15° with respect to the main axis of the foot P, (i.e. according to an angle of 15°±15° with respect to the transverse axis T perpendicular to the main axis P of the foot) as shown in FIG. 7.

The grooves 40 are advantageously positioned obliquely with respect to a longitudinal axis L of the shoe 100. The grooves 40 are substantially straight. They can also have a slight concavity as shown in FIGS. 2 and 3 while still propagating substantially transversally in a straight direction.

The grooves 40 can be continuous on either side of the sole 10, discontinuous, extending transversally over one or more portions of the sole, etc.

In this flexing zone 41, the outsole 15 does not comprise any element with an extra thickness breaking the creepage distance defined by the grooves 40, so as to not disturb the flexing guide line of the sole 10, in the flexing zone 41 and along the grooves 40.

This arrangement of the grooves 40 of the outsole 15 in this particular flexing zone 41 makes it possible to guide the folding of the shoe during the lateral unfolding of the anterior arch (by the exterior of the 5^(th) metatarsal head to the 1^(st) metatarsal head) during walking and taking support, like a genuine guide rail. Thus, the grooves 40 arranged in the forefoot make it possible to optimise the conducting of the movement of the unfolding of the step during walking, or running, the most efficiently as possible by minimising the resistance of the shoe during the unfolding of the foot. Thus, these grooves 40 have for objective to improve the supports and to optimise the unfolding of the foot during walking or running, and to improve the general balance of the athlete with a functional activity that is safer and more economical.

Whatever the structure of the sole 10 is around this flexing zone 41, the flexing fold of the shoe 100 is carried out naturally in the grooves 40 arranged in the thickness of the sole, in particular by the creation of one or more preferred flexing zones wherein the thickness of the sole 10, and in particular of the wearing outsole 15 is lower.

The applicant has observed that the shoe according to the invention made it possible to release the specific flexor muscle of the big toe. Indeed, it is frequent that the specific flexor muscle of the big toe is misused due to an incorrect position of the flexing fold of the shoe that is random or defined by the structure of the gripping means of the wearing outsole without actual control. Although the flexor muscle is supposed to be used substantially for propulsion, it is often used in the shoes of the prior art to fight against the eversion of the foot, i.e. as a lateral stabiliser of the subtalar joint by supplementing the inversor muscles (anterior and posterior tibial muscles). Thus, the energy spent to laterally stabilise the foot in the frontal plane will therefore not be used to advance in the sagittal plane and this is deleterious at the functional level. Also note that the degree of inversion or of eversion and the maintaining thereof during the taking of support also determine the harmful tensions on the internal arch of the foot during walking, thus reducing an overlying disorganisation of the skeleton.

Generally, it has been observed that the mobility of the metatarsal is not sufficiently developed in today's athletes. The current sports shoes and of the prior art share a large part of the responsibility in this lack of mobility because they do not allow a deformation of the interior arch of the foot, progressively rigidifying this zone. The correction of the positioning of the subtalar joint and the recentring of the support zone by the flexing zone 41 of the shoe at the head of the metatarsals make it possible to progressively reform the organisation of the forefoot and to retain the physiology thereof during the practice of sport, even during running over a long distance, such as a marathon.

The architectural configuration studied for the grooves 40 and therefore of the flexing fold of the forefoot of the shoe 100 makes it possible to fully respect the stress on the suro-achilleo-plantar system during walking or running. This substantially improves the global posture of the athlete and contributes to preventing muscular, tendon and joint injuries.

FIGS. 4 to 6 show, along a cross-section with respect to the longitudinal axis of the shoe, different embodiments of the structure of the outsole 15 in the flexing zone 41.

In a first embodiment shown in FIG. 4, the flexing zone 41 comprises a plurality of grooves t 40 oriented transversally and arranged in the thickness of the outsole 15, i.e. in its nominal thickness ep_(n). The grooves 40 can be identical or of different shapes, and/or of identical or different depths and/or of identical or different lengths. This embodiment is particularly suited for sports shoes that do not have any sculpture or cleats in this flexing zone 41, such as for example a football shoe. Such a shoe will be described in what follows in reference to FIG. 9. This embodiment, the outsole 15 comprises four grooves 40 forming four zones where the thickness of the outsole ep_(a) is less than the nominal thickness ep_(n) in this flexing zone 41 in the anterior part 12. These four grooves 40 thus form four flexing primer zones. Of course, the number of transversal grooves can be adapted according to the type of shoe and in particular the hardness of the sole. Thus, for a football shoe not having a random flexing zone in the anterior part, this embodiment is particularly well suited.

According to a second embodiment shown in FIG. 5, the structure of the sole 15 in the flexing zone 41 comprises, in addition to the four transversal grooves 40 at the level of which the thickness ep_(a) of the outsole 15 is less than its nominal thickness ep_(n) of the strips 42 with extra thickness (three strips are shown as an example) positioned in interval with the transversal grooves 40. These strips 42 with extra thickness have an extra thickness with respect to the nominal thickness ep_(n) of the outsole 15 in this flexing zone 41 of the anterior part 12. At these strips 42 of material with extra thickness, the thickness of the sole ep_(c) is greater than the nominal thickness ep_(n).

The strips 42 form means of gripping, in the form of flexible and deformable longitudinal strips, participating in the global gripping structure of the outsole 15. As shown in FIGS. 2 and 3, these strips 42 with extra thickness extend in the same direction as the transversal grooves 40. In a manner identical to the transversal grooves 40, these strips 42 with extra thickness also follow the general orientation of the flexing zone 41 and of the transversal grooves 40 in such a way that the strips 42 with extra thickness are oriented with an angle comprised between 0 and 30° with respect to the transverse axis T.

The strips 42 with extra thickness are advantageously positioned obliquely with respect to the longitudinal axis L of the shoe. The strips 42 with extra thickness are substantially straight. They can also have a slight concavity as shown in FIGS. 2 and 3 while still propagating in a substantially straight direction.

The strips 42 with extra thickness can be continuous on either side of the sole 10, discontinuous, or extend transversally over a portion or several portions of the outsole 15.

The strips 42 with extra thickness participate in the global structure of the gripping means of the outsole 15 in such a way that during the acceleration or braking phases, the particular structure of the outsole 15 supplemented by the positioning of the strips 42 with extra thickness oriented transversally form as a “metatarsal cleating” improving braking, anchoring, propulsion and acceleration when the anterior part 12 of the shoe 100 touches the ground first.

Of course, the number of grooves 40 and the number of strips 42 with extra thickness can be adapted according to the needs and the type of shoe to be made.

According to a third embodiment shown in FIG. 6, the outsole 15 comprises two transversal grooves 40 arranged in the thickness of the outsole 15. The grooves 40 are positioned in such a way as to edge said flexing zone 41, and thus defining two preferred primers at the periphery of the flexing zone 41 at the level of which the thickness ep_(a) of the outsole 15 is less than the nominal thickness ep_(n) of the outsole 15. Identically to the preceding embodiment, the flexing zone 41 also comprises strips 42 with extra thickness (three strips are shown as an example) defining gripping means of the shoe. However, in this embodiment, the recesses 40 a present between two adjacent strips 42 do not form grooves 40 as mentioned hereinabove because the thickness of the outsole at these recesses 40 a is not reduced and corresponds to the nominal thickness ep_(n) of the outsole 15. At these recesses 40 a, there is therefore no creation of a preferred primer to carry out a flexing fold. These recesses 40 a are therefore formed only by the presence of the strips 42 with extra thickness spaced apart from one another.

This embodiment is particularly shown particularly in FIG. 2 and in FIG. 3. In the embodiment shown in FIG. 2, the transversal grooves 40 at the periphery of the flexing zone 41 extend only over a portion of the outsole 15, and advantageously over a portion located in the vicinity of the external portion of the outsole 15.

Regardless of the embodiment, the grooves 40 create one or more primers in the anterior part 12 of the outsole 15 artificially reducing the hardness of the sole in this flexing zone 41 in such a way as to create a natural flexing of the shoe during walking in this flexing zone 41.

According to a second embodiment shown in FIG. 8, the decrease in the hardness of the sole 10 in the flexing zone 41 is carried out by the inclusion in the sole of a material M2 having characteristics different from the material M1 used for the rest of the sole 10 (i.e. for the posterior part, the central part and the anterior part outside of the flexing zone 41).

This second material M2 can be introduced into the outsole 15 as shown in FIG. 8, or into the midsole 16 (not shown), when the hardness of the sole 10 in this flexing zone is decreased by at least 10%.

According to a first alternative embodiment of this second example, the material M2 is of the same nature as the material M1 and has a density less than the material M1, typically a density less than 10%.

According to a second alternative of this second example, the material M2 is of a nature different from the material M1 and has a hardness less than the material M1, typically a hardness less than 10%.

The invention also has for object a sports shoe with rigid cleats, such as a football, rugby, etc. shoe, having rigid cleats (i.e. that cannot be deformed by hand) moulded or to be screwed.

Rigid cleats means cleats that have a hardness greater than 20 shore D shore.

Reference shall be made for example to document FR2945917 and FR2967874 fora complete description of such a shoe with cleats.

The characteristics described hereinabove for a walking or running shoe in reference to FIGS. 1 to 8 remain applicable for a shoe with cleats.

According to the embodiment shown in FIG. 9, the shoe with cleats 200 comprises a sole 210 that has, identically to the preceding description, a midsole (not visible and an outsole 215).

The outsole 215 comprises a plurality of rigid cleats 216 distributed between the anterior part 12 and the posterior part 13 intended to come into contact with the ground. In the embodiment of the invention shown in FIG. 9, the cleats 216 are so-called “moulded” cleats and are therefore secured and carried out during the moulding of the outsole 215. Alternatively, these cleats can be screwed cleats made of plastic or metal material by ad hoc fastening means. The cleats 216 are indifferently cleats with a conical, cylindrical, lamellar shape or any other shape that makes it possible to provide adherence on the ground.

The entire outsole 215, here including the moulded rigid cleats 216, is made of a material that has a hardness greater than or equal to 80 Shore A or 30 Shore D. Typically, the outsole 215 is made from a plastic material of the thermoplastic type or of a thermosetting material possibly reinforced with fibres of the nylon, glass or carbon type, the outsole 215 able to be an overmoulding or an assembly of several materials so as to obtain different mechanical properties at different locations of the sole 200.

The anterior part 12 of the sole 210 has a plurality of oblique transversal grooves 240 located in a flexing zone 241 that extends over a portion or on either side of the width of the sole 210 (i.e. between the interior and the exterior of the sole 210) and that originates facing or at the rear of the necks of the heads of the metatarsals (advantageously up to a maximum of 2 cm at the rear according to the type of shoe) and terminates facing or at the front of the metatarsal heads (and advantageously up to a maximum of 2 cm at the front according to the type of shoe).

In the embodiment shown in FIG. 9, the grooves 240 extend transversally on either side of the outsole 215, i.e. from the exterior to the interior of the shoe with cleats 200.

This embodiment is particularly shown in FIG. 4 described hereinabove.

Thus, in this embodiment, the flexing zone 241 comprises several flexing primers in the anterior part 12 of the outsole 15 in such a way as to decrease the hardness of the sole and thus create a flexing that is sufficiently natural of the shoe during walking or running in this flexing zone 241.

Carrying out such transversal grooves 240 in a rigid sole, made of plastic material, makes it possible to artificially create a flexing zone with a decreased hardness that is perfectly located in a defined zone of the anterior part which is in generally totally absent on this type of shoe with cleats, such as football shoes for example with soles made of rigid materials of the thermoplastic type.

The sports shoe according to the invention thus forms an elementary link in the prevention, protection, and improvement of the performance of the athlete. It further has the following additional advantages:

-   -   limitation of the risks of injury;     -   protection and fighting against mechanical and physiological         pain;     -   preservation of the biomechanics of the lower limbs, the pelvis,         and the back;     -   improvement of the venous system of the effort;     -   improvement in the venous draining of the foot and of the lower         limbs favouring the elimination of toxins;     -   improvement in performance;     -   improvement and respect of the three arches and of the three         support pillars of the foot;     -   improvement in comfort.

It goes without saying that other embodiments can be considered, without leaving the scope of the invention, the latter being in no way limited to the examples described and shown.

In particular, although the embodiments described hereinabove concern a jogging and football shoe, the invention can also relate to shoes provided for the practice of other sports such as rugby, American football, baseball, golf, trail running, walking, hiking or other sports. 

1. Sole of a shoe, extending in a longitudinal direction representative of a main axis of the foot, and having an anterior part that is adapted to receive the forefoot, a central part that is adapted to receive the midfoot and a posterior part that is adapted to receive the heel, said sole having in the anterior part a preferred flexing zone extending in an oblique direction with respect to the main axis of the foot.
 2. The sole according to claim 1, wherein said sole has in the anterior part a plurality of preferred flexing zones extending in an oblique direction with respect to the main axis of the foot.
 3. The sole according to claim 1, wherein said preferred flexing zone is located in the anterior part receiving the forefoot and as a projection of the metatarsal phalangeal heads of the foot.
 4. The sole according to claim 1, wherein said sole has, in the preferred flexing zone, a hardness at least 10% lower with respect to the rest of said sole.
 5. The sole according to claim 1, wherein said preferred flexing zone has a height, extending in a longitudinal direction, comprised between 3 and 40 mm.
 6. The sole according to claim 1, wherein said preferred flexing zone is oriented according to a flexing fold axis, itself oriented at an angle of 105°±15° with respect to the main axis of the foot.
 7. The sole according to claim 1, wherein said sole has, in the preferred flexing zone at least one groove oriented according to the flexing fold axis.
 8. The sole according to claim 1, wherein said sole is made of a first material and has, in the preferred flexing zone, an inclusion of a second material of a same nature and having a density less than a density of the first material used for the rest of the sole.
 9. The sole according to claim 8, wherein the second material has a density at least 10% less than the density of the first material.
 10. The sole according to claim 1, wherein said sole is made of a first material and has, in the preferred flexing zone, an inclusion of a second material of a different nature and having a hardness less than a hardness of the first material used for the rest of the sole.
 11. The sole according to claim 10, wherein the second material has a hardness at least 10% less than the hardness of the first material.
 12. The sole according to claim 1, wherein said preferred flexing zone is located at a distance comprised between 60 and 75% of the total length of the sole from its rear end.
 13. The sole according to claim 1, wherein said preferred flexing zone extends over a portion or over the entire width of the sole.
 14. The sole according to claim 1, wherein said sole has a strip with extra thickness located at an edge of said preferred flexing zone or at two edges of said preferred flexing zone.
 15. The sole according to claim 1, wherein strip with extra thickness is oriented according to a flexing fold axis, itself oriented at an angle of 105°±15° with respect to the main axis of the foot.
 16. The sole according to claim 1, wherein said strip with extra thickness forms a means of gripping of the anterior part of the outsole.
 17. The sole according to claim 1, wherein said sole is a flexible sole with an elastomer base or a rigid sole with a thermoplastic material base.
 18. The sole according to claim 1, wherein sole comprises an outsole intended to come into contact with the ground and a midsole, said preferred flexing zone extending in an oblique direction with respect to the main axis of the foot being arranged in said outsole.
 19. Shoe comprising a sole according to claim
 1. 20. The shoe according to claim 19, wherein said shoe is a sports shoe, or a running shoe, or a football shoe or a rugby shoe. 